Hi Connie. The rule you may be thinking of is about blank lines and the page change indicator. That rule is stated in Section 185.a of the Nemeth Code (Rule XXV--Format). The Nemeth Code does not mention box lines. Looking in Section 7 of Braille Formats 2011 (the edition for EBAE transcriptions), 7.2.1.d. says that a blank line cannot precede a bottom box line. I believe that a Nemeth format rule would override this, though. It is important to follow a spatially-arranged problem with a blank line. To avoid the odd look of a box line being surrounded by blank lines, is it possible not to box the material? If you choose to retain the box lines, then I vote for following the Nemeth rule and putting a blank line between the problem and the bottom box line.
Lindy